Do not use local override for language settings: always sync.

chrome/common/pref_names.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Constants for the names of various preferences, for easier changing.
 
 #ifndef CHROME_COMMON_PREF_NAMES_H_
 #define CHROME_COMMON_PREF_NAMES_H_
 #pragma once
 
 #include "build/build_config.h"
 
 namespace prefs {
 
 // Profile prefs
 extern const char kAppsPromoCounter[];
 extern const char kDefaultAppsInstalled[];
 extern const char kHomePageIsNewTabPage[];
 extern const char kHomePage[];
 extern const char kSessionExitedCleanly[];
 extern const char kRestoreOnStartup[];
 extern const char kURLsToRestoreOnStartup[];
 
 // For OS_CHROMEOS we maintain kApplicationLocale property in both local state
 // and user's profile.  Global property determines locale of login screen,
 // while user's profile determines his personal locale preference.
 extern const char kApplicationLocale[];
 #if defined(OS_CHROMEOS)
 extern const char kApplicationLocaleBackup[];
-extern const char kApplicationLocaleOverride[];
 extern const char kApplicationLocaleAccepted[];
 #endif
 
 extern const char kDefaultCharset[];
 extern const char kAcceptLanguages[];
 extern const char kStaticEncodings[];
 extern const char kPopupWhitelistedHosts[];
 extern const char kShowBookmarkBar[];
 extern const char kWebKitStandardFontIsSerif[];
 extern const char kWebKitFixedFontFamily[];
@@ skipping 404 matching lines @@
 extern const char kAuthNegotiateDelegateWhitelist[];
 extern const char kGSSAPILibraryName[];
 
 extern const char kKnownBackgroundPages[];
 
 extern const char kDisable3DAPIs[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_